An increasing number of surgical interventions is executed with the help of interventional instruments under the control of an imaging system that generates projections of the treated body region. A typical example are interventions in the cardio-vascular system during which often different instruments like (balloon) catheters, guide wires, stents or the like are applied sequentially or simultaneously. Moreover, specific functionalities of the imaging system are provided for different phases of an intervention and for the application of different instruments, wherein these functionalities nowadays must be started manually by a physician.